Sustaining Biodiversity: The Species Approach

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Chapter 11

• Sustaining Biodiversity The Species Approach

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SPECIES EXTINCTION

• Species can become extinct
• Locally A species is no longer found in an area
  it once inhabited but is still found elsewhere in
  the world.
• Marsh Deer, Blue Whale, Lake Sturgeon
• Ecologically Occurs when so few members of a
  species are left they no longer play its
  ecological role.
• Sea otter, California Spiny Lobster
• Globally (biologically) Species is no longer
  found on the earth.

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Global Extinction

• Some animals have become prematurely extinct
  because of human activities.

Figure 11-2
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Endangered and Threatened Species

• Endangered species so few individual survivors
  that it could soon become extinct.
• Threatened species still abundant in its natural
  range but is likely to become endangered in the
  near future.

Figure 11-3
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Fig. 11-3, p. 224
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SPECIES EXTINCTION

• Some species have characteristics that make them
  vulnerable to ecological and biological
  extinction.
• Floridas extinction

Figure 11-4
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Estimating extinction rates

• Scientists use measurements and models to
  estimate extinction rates.
• The International Union for the Conservation of
  Nature and Natural Resources (IUCN) publishes an
  annual Red List, listing the worlds threatened
  species.
• The 2004 Red List contains 15,589 species at risk
  for extinction.
• 1 out of every 4 mammal species
• 1 out of every 7 plant species
• 1 out of every 8 bird speices

Figure 11-5
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Estimating extinction rates is difficult because

• Extinction takes a long time on a human time
  scale and documentation is limited
• Many species are not identified
• We know little about the species we have
  identified

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SPECIES EXTINCTION

• Percentage of various species types threatened
  with premature extinction from human activities.

Figure 11-5
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IMPORTANCE OF WILD SPECIES

• Ecological services
• Control pests, store carbon, recycle nutrients
• Economic services
• Food, fuel, timber, paper, medicines
• Genetic information
• Recreational pleasure
• Ecotourism
• Biophilia affinity for nature

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HABITAT LOSS, DEGRADATION, AND FRAGMENTATION

• Conservation biologists summarize the most
  important causes of premature extinction as
  HIPPO
• Habitat destruction, degradation, and
  fragmentation
• Invasive species
• Population growth
• Pollution
• Overharvest

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HABITAT LOSS, DEGRADATION, AND FRAGMENTATION

• The greatest threat to a species is the loss,
  degradation, and fragmentation of where it lives.

Figure 11-7
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HABITAT LOSS, DEGRADATION, AND FRAGMENTATION

• Reduction in ranges of four wildlife species,
  mostly due to habitat loss and overharvest.

Figure 11-8
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Which species are most vulnerable?

• Specialist
• K strategist- low reproductive rate
• Contain desirable characteristics
• video

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Case Study A Disturbing Message from the Birds

• Human activities are causing serious declines in
  the populations of many bird species due to
  deforestation, introduction of nonnative species,
  nets in oceans, power lines, and buildings.

Figure 11-9
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INVASIVE SPECIES

• Many nonnative species provide us with food,
  medicine, and other benefits (like reduced soil
  erosionkudzu) but a a few can wipe out native
  species, disrupt ecosystems, and cause large
  economic losses.

Kudzu vine was introduced in the southeastern
U.S. to control erosion. It has taken over native
species habitats.
Figure 11-A
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INVASIVE SPECIES

• Many invasive species have been introduced
  intentionally.

Figure 11-11
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INVASIVE SPECIES

• Many invasive species have been introduced
  unintentionally.

Figure 11-11
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INVASIVE SPECIES

• The Argentina fire ant was introduced to Mobile,
  Alabama in 1932 from South America.
• Most probably from ships.
• No natural predators.
• Zebra Mussels in the Great Lakes

Figure 11-12
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INVASIVE SPECIES

• Prevention is the best way to reduce threats from
  invasive species, because once they arrive it is
  almost impossible to slow their spread.

Figure 11-13
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Characteristics of Successful Invader Species
Characteristics of Ecosystems Vulnerable to
Invader Species
Climate similar to habitat of invader
Absence of predators on invading species Early
successional systems Low diversity of
native species Absence of fire Disturbed by
human activities
High reproductive rate, short generation
time (r-selected species) Pioneer species
Long lived High dispersal rate Release
growth-inhibiting chemicals into soil
Generalists High genetic variability
Fig. 11-13, p. 236
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POPULATION GROWTH, POLLUTION, AND CLIMATE CHANGE

• Population growth, affluenza, and pollution have
  promoted the premature extinction of some
  species.
• Projected climate change threatens a number of
  species with premature extinction.
• Polar bears

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Pollution

• Each year pesticides
• Kill about 1/5th of the U.S. honeybee colonies.
• 67 million birds.
• 6 -14 million fish.
• Threaten 1/5th of the U.S.s endangered and
  threatened species.

Example of biomagnification of DDT in an aquatic
food chain.
Figure 11-15
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OVEREXPLOITATION

• Some protected species are killed for their
  valuable parts or are sold live to collectors.
• Legal and illegal trade in wildlife species used
  as pets or for decorative purposes threatens some
  species with extinction.
• Burmese python

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OVEREXPLOITATION

• Rhinoceros are often killed for their horns and
  sold illegally on the black market for decorative
  and medicinal purposes.

Figure 11-16
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Case Study Rising Demand for Bushmeat in Africa

• Bushmeat hunting has caused the local extinction
  of many animals in West Africa.
• Can spread disease such as HIV/AIDS and ebola
  virus.

Figure 11-17
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PROTECTING WILD SPECIES

• International treaties have helped reduce the
  international trade of endangered and threatened
  species, but enforcement is difficult.
• One of the most powerful is the 1975 Convention
  on International Trade of Endangered Species
  (CITES).
• Signed by 169 countries, lists 900 species that
  cannot be commercially traded.

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The U.S. Endangered Species Act

• One of the worlds most far-reaching and
  controversial environmental laws is the 1973 U.S.
  Endangered Species Act (ESA).
• ESA forbids federal agencies (besides defense
  department) to carry out / fund projects that
  would jeopardize an endangered species.
• ESA makes it illegal for Americans to engage in
  commerce associated with or hunt / kill / collect
  endangered or threatened species.

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Other acts/treaties to protect species

• National Marine Fisheries Service- id and protect
  threatened or endangered marine species
• US Fish and Wildlife Service- id and protect
  threatened or endangered terrestrial species

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PROTECTING WILD SPECIES

• Gene banks, botanical gardens and using farms to
  raise threatened species can help prevent
  extinction, but these options lack funding and
  storage space.
• Zoos and aquariums can help protect endangered
  animal species by preserving some individuals
  with the long-term goal of reintroduction, but
  suffer from lack of space and money.

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RECONCILIATION ECOLOGY

• Reconciliation ecology involves finding ways to
  share places we dominate with other species.
• Replacing monoculture grasses with native
  species.
• Maintaining habitats for insect eating bats can
  keep down unwanted insects.
• Reduction and elimination of pesticides to
  protect non-target organisms (such as vital
  insect pollinators).

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What Can You Do?
Protecting Species
Do not buy furs, ivory products, and other
materials made from endangered or threatened
animal species. Do not buy wood and paper
products produced by cutting remaining
old-growth forests in the tropics. Do not buy
birds, snakes, turtles, tropical fish, and other
animals that are taken from the wild. Do not
buy orchids, cacti, and other plants that are
taken from the wild. Spread the word. Talk to
your friends and relatives about this problem and
what they can do about it.
Fig. 11-21, p. 246